Ask the Master Gardeners: August 2011
Guadalupe County Master Gardeners is responsible for this content, which is not edited by the Wilson County News or wilsoncountynews.com.
Q: As this drought continues, I am really worried about my large trees. What should I be doing?
A: If you’ve let the tree decline too much, there isn’t much that can be done to reverse the dying process. However, if you catch the problem soon enough, you can save your trees through watering, fertilizing, and by removing surrounding weeds and grass which compete for water.
Early signs of damage, according to AgriLife Extension Service’s Kathy Fiebig, are yellowing leaves and premature leaf drop all over the crown of the tree. As the damage gets worse, leaves will die from the bottom of the tree upward, and from the inside of the canopy outward. On some of my shrubs, the leaves wilt and burn along the edges. If you are counting on lawn watering to maintain your trees, that is not enough. Fiebig suggests giving 28 gallons of water a week to small one-year-old trees, 56 gallons a week to two-year-old trees and 112 gallons a week to three-year-old trees. (I’ve been giving 60 gallons every two weeks to my older trees in addition to lawn watering.) AgriLife Horticulturist Marty Baker recommends applying water in a donut-shaped pattern starting about five feet from the base of medium to large trees, out to about five feet beyond the tree’s drip line.
Fiebig warns that trees already stressed by the drought can be killed by a heavy application of herbicide in the root zone. Avoid soil-activated herbicides around trees.
For future reference, you may want a list of drought tolerant plants. A good one is found in Aggie-horticulture: http://www.plantanswers.com/drought_tolerance_plants.htm.
Q: I’ve been hearing about the disease Citrus Greening and am worried about the insects I see around my citrus tree. Could I have Asian citrus psyllids?
A: First of all, go to www.SaveOurCitrus.org to learn about the disease. It has not been found around Guadalupe County yet, but we should all be alert. Not all of the gnat-sized Asian citrus psyllids carry the disease-causing bacteria, but they can still damage citrus plants and trees by stunting the growth of new shoots. If you suspect the disease, contact the State Department of Agriculture. Do not transport citrus plants. Another website: www.aphis.usda.gov/plant_health/plant_pest_info/citrus_greening/index.shtml.
Q: I just accidentally touched a poison ivy plant and would like you to give your readers information on what to do immediately after exposure.
A: Within the first ten minutes, clean your skin with isopropyl alcohol (when this happened to me I used hand sanitizer containing ethyl alcohol. Maybe I was just lucky). Wash your skin with cold water (hot opens the pores). Shower with soap and warm water. Wipe your clothes, shoes, and tools with alcohol and water. This information from the Texas Workers’ Compensation Commission is quoted in Doug Welsh’s Texas Garden Almanac.
Clara Mae Marcotte is a Texas Master Gardener with the Texas AgriLife Extension. If you have a question to be answered, call the Master Gardeners at 830-379-1972 or leave a message to be answered. The website is guadalupecountymastergardeners.org. The Master Gardener research library is open Mondays from 8:30 to noon, on the second floor of the Texas AgriLife Extension building, 210 East Live Oak in Seguin.